Expansion reamer



Jan. 3l, 1939. @-EQJHPOHLMA'N v 2,145,370

ExPANs'IoN BEAMER Filed May 28, 1936 Patented Jan. 31, 1939 UNTED STATES il; i

PATENT orifice 10 Claims.

tion to provide a reamer so constructed that the reaming operation includes both roughing and 15 finishing of a cylindrical hole which is accomplished by simultaneous multiple cuts.

It is a further object of the present invention to provide a reamer of this character which is adjustable so as to vary its diameter to adapt it particularly, but not exclusively, for use in standard gauge work where the hole being reamed is above or below the standard gauge.

It is a further object of the present invention to provide a reamer in which the radial adjust- 25 ment of the cutting blades may be easily accomplished and definitely and accurately maintained and controlled.

It is a still further object of the present invention to provide an expansion reamer which is of 30 simple form, and which is susceptible of cheap manufacture, yet which has a comparatively long useful life in service.

Other objects and advantages of this invention will appear in the following description and ap- 35 pended claims, reference being had to the accompanying drawing forming a part of this speciiication wherein a preferred embodiment of the present invention is illustrated.

The present application is a continuation-in- 40 part of my co-pending application Serial No. 635,091, iiled September 27, 1932 and is related to my co-pending application Serial No. 635,092, led September 27, 1932, now United States Patent No. 2,063,753, dated December 8, 1936.

In the drawing, wherein like reference characters designate corresponding parts in the several views,

Fig. l, is an elevational view of a reamer constructed in accordance with the present invention;

Fig. 2 is an end elevational view of the reamer shown in Fig. 1;

Fig. 3 is a sectional view taken substantially on the line 3--3 of Fig. 1 in the direction of the arrows;

Fig. 4 is a sectional view taken substantially on the line 4-4 of Fig. 1 in the direction oi the arrows;

Fig. 5 is an elevational view showing particularly the construction of one of the finishing teeth; 5

Fig. 6 is an elevational View showing particularly the construction of one of the roughing teeth;

Fig. 7 is an elevational view showing particularly the construction of one of the semi-roughing teeth.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangementy of parts illustrated in the accompanying drawing, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation, and it is not intended to limit the invention claimed herein beyond the requirements of the prior art.

A preferred form of reamer embodying the present invention is formed of a cylindrical body I0, fluted as indicated at Il and l2 to provide successively arranged roughing, semi-roughing and nishing teeth i4, HSA and l5, of which the iiutes dening the former are cut to a greater depth than are the utes defining the latter. Three sets of teeth I4, [4A and l5 are chamfered at their forward ends as shown in Figs. 5, 6 and 7 and as there indicated at I6, IEA and l1, the angle of chamfer of the teeth M being approximately iifty degrees, while that of the semiroughing teeth MA is approximately forty-five degrees and that of the finishing teeth l5 is approximately forty degrees. The roughing and semi-roughing teeth I4 and MA are tapered in the direction of their length adjacent their forward ends, as indicated at Ill and H8. For the remainder of their length the teeth I4 and MA have substantially the same radial extent as the finishing teeth.

By the difference in angle of the chamfer on the forwardcutting ends of the roughing, semi roughing and nishing teeth I4, MA and l5, the cutting edge of the charnfer of the roughing teeth |12- is of the `greatest degree of angle and leads the cutting edge on the chamfer of the semiroughing teeth. The cutting edge of the chamfer of the semi-roughing teeth MA is of a lesser degree of angle than that of the roughing teeth, and leads the cutting edge on the chamfer of the finishing teeth, and the cutting edge on the chamfer of the finishing teeth I5 is of a lesser degree of angle than that of the chamfer on the semi-roughing teeth. These teeth thus make multiple cuts which, due to the multiple stepped angles applied to the chamfered teeth, make the cuts alternate simultaneously. Each of said cuts thereby also turns out a diierent shaped chip. These alternating cuts eliminate chattering of the reamer during the cut and produce a smoother nish in the hole than has previously been possible by use of a single cutting reamer.

The multiple stepped cuts are simultaneously accomplished because of the position of the multiple angles of the chamfered portions with relation to each other within the circumference of a radial plane. The bulk of the stock is thus removed from the hole by the roughing and semi-roughing teeth and the reamed hole is continually sized and smoothed by the finishing teeth. During the operation, the roughing and semi-roughing teeth cooperate back of their forward ends since they are of substantially the same radial extent as the nishing teeth.

The provision of the separate teeth making multiple types of cuts may be applied to any type of reamer construction. As here shown by way of example only, the invention is applied particularly to an expansion reamer construction. The body I0 of the reamer accordingly is made radially expansible and contractable, and to this end it is formed with a bore I8 and is slotted as indicated at I9 and 20. The slots I9 and 20 extend vertically from the bottom of the flutes I2 into the bore and the slots I9 extend axially from the forward end to a point short of the slots 20 in the heel end. The slots I9 and 20 extend longitudinally of the reamer blades on a plurality of substantially parallel lines extending circumferentially thereof. The slots I9 consist of alternate short sections I9a and longer sections I9b. The slots 20 consist of alternate short sections 20a and longer sections 2017. The short sections I9a extend on substantially the same line as the longer sections 2Gb, but are separated by an unslotted island or member 40. The longer sections I9b extend on substantially the same line as the shorter sections 20a but are separated by an unslotted island or member 4I. Each longitudinal slot thus consists of two separate slots, one, the longer, extending approximately two-thirds of the length of the reamer blade and the other, the shorter, extending on substantially the same line but for a distance less than approximately onethird of the length of the reamer blade. By virtue of the square corners at the open ends of the shorter slots the balls and cylindrical pins cannot locate themselves' in such slots. The ends of the' longer slots preferably are beveled as shown to permit the balls and pins to locate themselves properly by receding into the beveled slots. The longer and shorter slots extend alternately on lines equally spaced around the circumference of the reamer so that the unslotted islands or members 40 and 4I are in staggered relation to each other. Ihe islands or members 40 and 4I function mechanically as a. pivoting or a hinge point from which the reamerblades may be deflected.

The internal end portions of the reamer blades are provided with shoulders which are chamrfered only at points adjacent the longer slots I9b and 2Gb. Thus, a lead is provided so that the locking balls I2I will be forced only into the longer slotshIQbr, and the pins I I9 will be forced only into the longer slots 20h. Since the islands or members 4E! or 4I can be considered as the line of a fulcrum, and the reamer blades adjacent such slots can be considered as a system of levers, it will be apparent that the blades adjacent the longer slots will be longer levers than the' blades adjacent the shorter slots. Accordingly, thearrangernent here shown, permits the exerting of the required effort to secure expansion of the reamer blades only at points on the blades where the greatest mechanical advantage is exerted, thus facilitating the expansion of the reamer blades. By reason of this construction, any expansive force applied interiorly to the bore will effect enlargement of the' body radially, the expansive force being applied by reason of the bore being made of tapering shape to fit a corresponding tapered mandrel 2| along which, if the body be moved longitudinally, a radial movement of the blades will be effected.

In order that this axial movement along the mandrel may be effected and controlled, the mandrel is bored and tapped from the forward end as indicated at 22, and receives in this tapped bore the screw 23 which is provided with an enlarged head 24 seated in a counterbore 25 in the forward end of the body. The shoulder 26 in the counterbore is undercut forming a short taper to correspond with the taper on the triangular collar 26A. The head of the screw has a shoulder formed by a radius which intersects the face angle on one side of the triangle collar at 26B. The shoulder on the head 24 of the screw 23 will serve two purposes: rst, it will turn very easily when adjusting the screw, and second, it will properly locate itself to the taper face on triangle collar at 25B and assist the triangle collar and locking balls to assume their proper places in the tapered slots I22 provided in the forward end of the shell or body I0. This construction provides a iloating triangular collar 26A which will be self-locating upon the application of forces thereon. The collar 26A can pivot as a unit on the line contact with the curved shoulder of the member 24 and thus accommodate, by such movement, any slight manufacturing Variations which otherwise might cause the exertion of unequal pressure on the balls I2I (Iig the tapered slots I22 on the ends of the slots The triangular ycollar encircle's the screw 23 so that the screw, triangular collar and body are interlocked and the latter prevented from radial movement except in response to axial movement of the body on the arbor. The arbor 2| is formed as an integral part of the shank 21 which may be straight or of any of the conventional tapers to be received in the collet or spindle of a machine' tool. The arbor is threaded, as indicated at 29, where it connects with the shank, and on this threaded portion carries a nut 29 formed with a plurality of uniformly spaced sockets 30 in any one of which a pin or Spanner wrench may be engaged, so that the nut may be turned. The nut 29 is counterbored and in this counterbore receives a collar 3l which is formed with a body so that it may move slidably over the threaded portion 28. The collar on the front is beveled, this bevel coinciding with the bevel on the heel of the reamerl This collar also supports driving keys 32 in slots 33, by which a positive driving connection between the body I0 and the arbor 2I is eifected, the keys engaging in radial slots 33 in the rear end of the body and in axially arranged ,slots 34 in the arbor. The slots 34 are elongated to provide for movement of the body along the arbor without disarranging the connection between the keys and thebody. The collar 3| equalizes the' pressures on the slots exerted by the cylindrical pins and locks the shell firmly to the mandrel through a cylindrical pin in each of the four slots which will hold all four sections of the shell firmly together on the tapered mandrel. The tapered thrust collar thus bears only on the cylindrical pins and thrusts them partly into the tapered slots |25 in the shell so as to equalize the sections in the circumference, locking them rmly to the tapered mandrel.

Cylindrical pins and or rollers IIS are shown at the heel of the reamer and are journalled in recessed slot portions |25, with the thrust collar 3| encircled by the counterbore in the lock nut 29. The counterbore in the lock nut 29 extends past the thrust collar to form an extension which will serve to hold the four cylindrical pins ||9 from dropping out of the beveled slots |25. In the forward end there is a locking screw with a triangular collar encircling the screw 23. The side of the triangular collar 26A contacts the head 2li of the screw 23 at a point 25B on a curved surface of the head 24. This curved surface gives the triangular collar 26A a freedom movement necessary to properly locate the balls i2i and the pins H9 in the tapered slots 22 and |25 provided in the slots |91) and 2Gb. Adjacent the opposite face of the` triangular collar 25A, a ball race or groove |2|) is provided to receive the hardened steel balls |2| inserted in the said race or groove |20. The triangular collar bears only on the steel balls |2| and thrusts them partly into the tapered slots |22 in the slots leb in the end of the shell, thus equalizing the movement of the blades in the sections of the circumference. Four sections are provided the circumference of the body portion, Which are formed by longitudinally extending slotsv |91) and 2Gb which extend approximately two-thirds of the length of the reamer blades. Four sections are also provided in thev circumference of the body portion, which are formed by shorter slots lea and 2M and which extend less than approximately one-third of the longitudinal length of the reamer blades. Thus the body of the reamer is divided into eight sections by the action of the slots. The unslotted portions d!)l and 4| act as a tie between the slotted portions, and act as hinges cr pivot points for the four sections thus formed. The increase or decrease of the diameter of the shell is effected by movement of the separated blades about the parts 4|] and 4| acting aspivoting points. The shell or body is locked'flrmly to the tapered mandrel.

The head 24 of the screw is provided with a tool seat 35, to permit turning of the screw so as to properly position the head with reference to the arbor and thereafter position the body at the proper point on the arbor. If the body is to be radially extended, the nut 29 is released and backed up toward the shank 21, after which the rotation of the screw 23, so as to move the head toward the mandrel, will slide the body back on the latter, effecting the radial expansion desired. W hen expanded to the proper extent, the nut 29 is tightened, thus forcing it against the collar 3| and the latter against the heel of the body so that further axial movement of the body is prevented but the radial adjustment maintained, because the body is then positioned at a definite point on the arbor. The collar 3|, while not bearing directly on the key 32, serves to keep the latter in place when engaged with the heel of the' body.

In reducing' the diameter, the reverse of these operations is carried out, the screw 23 being backed out and the nut 29 employed to force the body alongthe arbor, until its movement is arrested by the head 24 of the screw 23.

The locking device composed of the locking nut 29, the collar 3|, the screw 23 and the triangular collar 26A, can be used with various types of reamer constructions, such for example as any inserted blade type having a slotted body in` which the blades are to be locked, This locking device may also be used on any other types of cutting tools having a slotted body in which blades or cutters are inserted and removably locked in position.

It is to be understood that the invention as herein disclosed is shown as applied in but one of its preferred embodiments. The invention is applicable to cutting tools of which a reamer is but one type. Other cutting tools. werel a plurality of' separate blades forming a multiple stepped cut are employed for producing different types of cuts in the work piece, such for example as cutter heads, facing tools, end mills, countersinks and chamfering tools, and the like, may also utilize to advantage the invention herein disclosed. The invention, therefore, is not limited in its application to reamers only.

I claim:

1. A cutting tool comprising a body uted axially to provide -successive roughing, semiroughing and finishing teeth chamfered at different angles, the roughing and semi-roughing teeth at the forward end of the body being tapered to reduce their radial extent and provide a. stepped cutting of the Work piece.

2. A reamer comprising a. cylindricall body lluted axially to provide successive roughng and finishing teeth of which the former are tapered at the forward end of the body to reduce their radial extent, both the roughing and finishing teeth being chamfered at their forward ends, the angle of chamfer of the finishing teeth to a plane tangent to the body being less than the corresponding angle to the roughing teeth to said plane.

3. A reamer comprising a cylindrical body fluted axially and chamfered at different angles to provide successive roughing, semi-roughing and finishing teeth, the roughing and semiroughing teeth at the forward end of the body being tapered to reduce their radial extent, the 4angle of chamfer of the finishing teeth to a plane tangent to the body being less than the corresponding angle of either the roughing or the semi-roughing teeth.

4. A reamer comprising a cylindrical body flut-ed axially and chamfered at different angles to provide successive roughing and nishing teeth of which the former are each provided with a cutting edge of a less radial extent and greater longitudinal length than the cutting edge of said finishing teeth, the angle of chamfer of the iinishing teeth to a plane tangent to the body being less than the corresponding angle of the roughing teeth, the uting of the body being of a greater depth in front of the roughing teeth than in front of the iinishing teeth.

5. A reamer luted axially of the body and ch-amfered at different angles to provide intercurrent roughing, semi-roughing and finishing teeth, the roughing teeth having less radial extent and a greater cutting angle than the semiroughing and finishing teeth and adapted to make a cut removing more metal stock than is removed by the semi-roughing and finishing teeth, said finishing teeth having a chamfered portion adapted to continue the cut made by a preceding roughing or semi-roughing tooth and to complete a finished cut at the radial extent of said finishing tooth.

6. A reamer fiuted axially of the body to provide intercurrent roughing, semi-roughing and finishing teeth, each finishing tooth having a face portion lying in a substantially radial plane and each roughing and semi-roughing tooth being of a less radial extent than a succeeding finishing tooth and having a face portion lying in a plane extending at an angle to the radial plane of a following finishing tooth, whereby the roughing and semi-roughing teeth cut a rolled chip from the metal stock and the finishing teeth cut a flake chip therefrom, the ends of said teeth being chamfered and arranged to control the amount of metal removed by each of said teeth whereby the roughing teeth are permitted to remove more stock from the metal work piece than are the semi-roughing teeth, and the finishing teeth are permitted to remove less stock from the work piece than are the semi-roughing teeth.

7. A reamer comprising a fluted cylindrical body having roughing, semi-roughing and finishing teeth alternately disposed around its circumference, said nishing and semi-roughing teeth having cutting faces lying in substantially radial planes, said roughing teeth having cutting faces lying in planes tangential to the circumference of said body and at an angle to the radial planes of the cutting faces of the finishing and semiroughing teeth, thereby forming a rake on the roughing teeth greater than the rake on the finishing and semi-roughing teeth, said finishing teeth having a lesser longitudinal length than the longitudinal length of said semi-roughing and roughing teeth, and said roughing teeth having a lesser radial extent throughout a portion of their length than said finishing teeth, and a chamfered end on each of said teeth, whereby each roughing tooth is permitted to remove more stock from a metal work piece than is removed by a semiroughing tooth, and less stock is removed from the work piece by a finishing tooth than is removed by a semi-roughing tooth.

8. A tool adapted to simultaneously rough and finish a cylindrical surface cut and comprising a body portion having teeth arranged axially and chamfered at different angles to provide a plurality of roughing, semi-roughing and finishing cutters, each of said types of cutters being adapted to remove a particular type of chip of a controlled thickness, said roughing teeth being adapted to cut a relatively thicker chip than said semi-roughing teeth, and said finishing teeth being adapted to cut a relatively thinner chip than said semi-roughing teeth.

9. A reamer comprising a peripherally toothed body having a tapered bore and formed with a plurality of slots extending axially from opposite ends and from the surface into said bore, to provide a plurality of separated blades, the slots opening at one end alternately extending for greater land lesser distances of axial extent and terminating short of similarly arranged slots opening at the other end of the reamer to form a plurality of unslotted sections arranged in st-aggered relation about the periphery of the reamer body, a tapered arbor on which said body is received, and means for effecting movement of said body along said arbor and comprising a screw having an interlocking connection with the body at the forward end, and a locking nut threaded n the arbor and operatively connected with the other end of the body, said operative connections comprising driving keys seated in slots in the rear end of the body adjacent the longer slots in the reamer body and projecting into axial slots formed in the arbor, and a collar encircling the arbor and bearing against said keys to hold said keys in slots provided in the shell or body whereby the separate blades may be expanded by forces exerted on the blades adjacent the longest slotted portions upon movement of said body longitudinally of said arbor, and a lock nut engaging said collar.

10. A reamer comprising a peripherally toothed body having a tapered bore and formed with a plurality of slots extending axially from opposite ends and from the surface into said bore to provide a plurality of separated blades, the slots opening at one end alternately extending for greater and lesser distances of axial extent and terminating short of similarly arranged slots opening at the other end of the reamer to form a plurality of unslotted sections arranged in staggered relation about the periphery of the reamer body, a tapered arbor on which said body is received, and means for effecting its movement along said arbor and comprising a screw having an interlocking connection with the body at the forward end, and a locking nut threaded on the arbor and operatively connected with the other end of the body, said operative connections comprising driving members journalled in the rear end of the body adjacent the longer slots in the reamer body and projecting into axial slots formed in the arbor, a collar encircling the arbor whereby the separate blades may be expanded by forces exerted on the blades adjacent the longest slotted portions upon movement of said body longitudinally of said arbor, and a lock nut having a counterbore in which said collar is seated.

EDWARD J. POHLMAN.

A CERTIFICATE OF CORRECTION. Patent No. 2,1'LL5.,570. January 51y 1959'.

` EDWARD J. POHLMAN. l 4 It is' hereby certified that error appears inthe printed.. specification of' the above numbered patent-.requiring correction es follows Page 5 second column, line )45,clai-m2, for the word "to,"l first occurrence, read of; and that the said Letters Patent should be reed with this correction therein that the same may conform to the recorciof thecase in the Patent Office..

signed and Vseele@ this 18th dgy or April, A. 1). 1959.

Henry Van Arsdale (Seal) Acting vCommissioner of Patents 

